1. Field
The present disclosure relates to a method and composition for separating liquid hydrocarbon compounds from water or land, such as beaches. This disclosure also relates to a foam for the selective absorption of oil from water or land. The oil may be recovered from the foam. The foam is particularly useful for the removal of oil spills from a body of water or land.
2. Description of the Prior Art
There is considerable concern about the biological impact of oil spills and the health and economic effects upon individuals that reside and make their living from the areas surrounding the spill. Oils spills are often due to releases from tankers, barges, or from offshore drilling operations. Oil spills occur in rivers in addition to oceans, seas, gulfs, and on land. Cleaning up oil spills from the surface of the water and below the surface of the water is a challenging and costly procedure. Oil may be present on and under the surface of a body of water and on any land that the water touches. The oil damages and kills aquatic and terrestrial life, affects food sources obtained from those waters, and ruins neighboring beaches. Areas affected by oil spills are economically affected due to the inability to practice livelihoods dependent upon the waters and beaches such as fishing, shrimping, and tourism. In another embodiment, the ability to separate oil from water in an industrial environment is also useful.
Many solutions have been offered regarding compositions to clean up oil spills. Oil spills are typically partially or completely surrounded by booms. After which the oil is collected and pumped to a storage area or burned off. Recovery systems or burning off the oil are challenging due to the fact that oil spills usually cover a large area and the water is moving.
Various oil absorbing materials have been used in the past such as straw or vermiculite, sand, kieselguhr, diatomaceous earth, peat fibers, polymers, and sawdust. Such materials were spread on the oil spill and collected with the oil absorbed on or absorbed into the material. Once oil at or below the surface of water or from land is removed, there was a problem of how to dispose of the oil and/or the substances used to remove the oil from the water or land. These oil-coated materials are waste products. Another challenge to recovery of the oil is that many of the materials absorb a large amount of water. This decreases the amount of oil that the material may absorb.
It has been proposed in U.S. Pat. No. 3,819,514 to utilize a foam comprising ethylene-alkyl acrylate copolymer to selectively absorb oil from oil water mixtures. These foams require a copolymer having a minimum melt index of 800 grams/10 minutes, preferably in the range of 1000-2000 grams/10 minutes. The low molecular weight of these copolymers results in a foam of low physical properties and questionable durability to afford repeated use for absorbing oil. Furthermore, the open cell content of these foams relies upon the rheology of the copolymer during expansion as no crushing of the foam is utilized. This results in higher foam density and lower open cell content as compared to foam utilizing a crushing step in its preparation. Both of these attributes limit the foam's capability for oil absorption. As shown in the examples of U.S. Pat. No. 3,819,514, oil absorption comprises 10-13 times the foam weight.
It is desirable to provide foams having improved capacity for absorbing oil as compared to the copolymers in U.S. Pat. No. 3,819,514. It would also be desirable to provide a foam that can be utilized a plurality of times by squeezing the foam to remove absorbed oil therefrom and then reusing it for oil recovery. Furthermore, it would be desirable to provide a foam that is biodegradable so that after use it can be placed in a landfill where it will degrade.